Superstring theory is a theory that attempts to unify all of the forces, but it is not experimentally verifiable with current scientific technology. Despite the mathematical completeness of the theory, the difficulty of verification has led to an ongoing debate about its validity. Can superstring theory be recognized as science?
Einstein’s final dream, famous for his theory of relativity, was to unify all the forces in the world. His final quest, dubbed the “unified field theory,” was unsuccessful, and there have been countless physicists attempting to do so ever since. Under the view that physics is broadly divided into relativity, which deals with the macroscopic world, and quantum mechanics, which deals with the microscopic world, three forces that can be described within the microscopic world have already been unified through various efforts: the electromagnetic force, the weak nuclear force, and the strong nuclear force. However, since only gravity is explained within relativity, which deals with the macroscopic world, the final process of merging the three unified forces with gravity is not smooth. Superstring theory has emerged as a puzzle of unified field theory that has been proposed to overcome this difficulty, and this article will examine the validity of this theory.
Superstring theory is a theory based on quantum mechanics, so it requires the reproduction of such a microscopic world, especially the conditions at the beginning of the creation of the universe, which is the environment for the verification of superstring theory. However, such a situation cannot be reproduced with current technology. In addition, a theory in science can only exist within the boundaries of science if it can be proven by experiment. Should we blame the inability of science to verify superstring theory on a lack of state-of-the-art technology? I don’t think so. Superstring theory is criticized for trying to do it all within its own mathematical logic, but is so obsessed with mathematical completeness for its “theoretical” proof that the conclusions it states are unlikely to be verifiable experimentally – it demands experimental conditions that go beyond simply realizing the conditions of the early universe. It’s as if superstring theory is claiming for itself a realm of ideals that can only exist within a mathematical logic. In order to keep it within the bounds of science, it is incumbent upon the researchers of superstring theory to come up with a way to verify the theory that is not ‘ideal’; otherwise, while they are free to continue working on their theory, they are not free to claim its validity. Karl Popper, the philosopher of science, advocated the ‘principle of disprovability’, which states that a scientific theory is only good if it is capable of being disproved. It seems unlikely that superstring theory is a good theory. There is no way to disprove it, at least not yet, and it seems unlikely that it will ever be possible.
The current state of math is insufficient to deal with superstring theory. It is said that many advances in math have been made just to deal with superstring theory, and that the math that describes it is intractable. Also, as mentioned earlier, the theory has no experimental correlations whatsoever. In other words, superstring theory appears to be speculative. If the language of science is mathematics, then it would be more appropriate to view string theory as merely a branch of philosophy described in the language of mathematics. But where is the value of string theory in that view? No one would think that string theory could have the same impact on the human intellect that philosophy has had on the human intellect. It may not be a science, but it cannot reveal its value without being a science. It is certainly not a theory that seeks to limit its significance to the advancement of mathematics to describe itself.
So why are researchers obsessed with superstring theory? Physicists are attracted to the symmetries found in the laws of physics. Superstring theory also fascinates many physicists because of its symmetries. They believe that there is physical truth in symmetry. But can a physical theory only be right if it implies symmetry? Kepler, the famous physicist and astronomer, tried to explain the arrangement of the planets around the sun solely in terms of the geometric symmetries of the five tetrahedra and spheres in the world. It seemed to work, but the solar system, which should have only six planets in such a structure, contained eight planets, and the orbits of the planets, which should have been spherical, were ironically modified to elliptical orbits by Kepler’s law, which he had discovered. Interestingly, Kepler was never able to abandon his belief in geometric symmetry. This historical anecdote seems to foreshadow what the current generation of superstring researchers will face if superstring theory turns out to be wrong: a scientist will have to base his or her research on scientific facts alone. While a scientist’s personal beliefs may be the source of his or her will and enthusiasm for research, they are not the source of his or her scientific thinking. Where, then, will the competence of so many scientists be focused if it is based solely on reason?
Superstring theory has been criticized by some as an unfortunate theory that was discovered a century too early, an opinion that is often held by Edward Witten, a leading superstring theory researcher. Edward Witten is a giant in the world of theoretical physics, and his influence in the field is such that he has been described as “as brilliant as everyone here is, he has reached a level of godlikeness that cannot be surpassed.” That may be true. But I think it’s more accurate to say that it’s on the borderline between precocious and immature. Superstring theory has very little experimental proof, and the experimental evidence on which it is based is very weak. Where is the evidence? If superstring theory is a theory that can be talked about in the realm of particle physics, then the current accepted and definitive theory in particle physics is the ‘Standard Model’ theory. While the Standard Model is considered to be close to being experimentally proven with the discovery of the Higgs boson, it still has many gaps that need to be filled in and elucidated. We all know that a building can only stand on a strong foundation, so maybe we should focus more on the parts of the theory that we know more about now, where we can find more clarity. In that clarity, we might find the real clues and the foundation for superstring theory, which is currently just a collection of complex mathematical expressions. Of course, there is still plenty of work to be done to make superstring theory a viable candidate for a “unified field theory,” but hopefully physicists will move away from their blind obsession with mathematical symmetries and open their minds to many other areas of theoretical physics.
I’d like to end with a quote from physicist Steven Weinberg, who was once at the forefront of superstring theory: “I don’t want to discourage string theorists. But the world may be as we have always known it: the world of the Standard Model and general relativity.”
